Induction motor and sequence reactance

In summary, in induction motors, there are three components in any network: positive sequence, negative sequence, and zero sequence. The running reactance, starter reactance, and standstill reactance in induction motors are all related to the impedance of the motor in the positive and negative sequence systems. The impedance can be determined using the formula ZM = 1/(ILR/IrM)*UrM/sqrt(3)/IrM=UrM^2/SrM//(ILR/IrM), where UrM is the rated voltage, IrM is the rated current, SrM is the rated apparent power, PrM is the rated motor power, effrM is the rated motor efficiency, COSfiTM is the rated
  • #1
honyeehong8692
16
0
Hello! This is my second post about sequence reactances. This time- its in induction motor.

To my understanding ( once again ) -

In any network (symmetrical or unsymmetrical) , there would be 3 components- positive sequence component, negative sequence component and zero sequence component.

Question:

In induction motors, what do the: running reactance, starter reactance and standstill reactance mean?

and,

Do anyone of them signify/mean the positive sequence reactance of a unsymmetrical fault system?
 
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  • #2
BTW, a prompt reply is very much appreciated. Please and thank you!
 
  • #3
According to IEC 60909-0 Ch. 3.8 Asynchronous motors 3.8.1 General:
The impedance ZM = R M + jXM of asynchronous motors in the positive- and negative-sequence systems can be determined by:
ZM=1/(ILR/IrM)*UrM/sqrt(3)/IrM=UrM^2/SrM//(ILR/IrM)
Where
UrM is the rated voltage of the motor;
IrM is the rated current of the motor;
SrM is the rated apparent power of the motor (SrM = PrM/(effrM* COSfiTM);
PrM is the rated motor power [kW]
effrM is the rated motor efficiency
COSfiTM is the rated motor power factor
ILR/IrM is the ratio of the locked-rotor current to the rated current of the motor.
 

1. What is an induction motor?

An induction motor is an AC motor that uses electromagnetic induction to produce motion. It is the most commonly used type of motor in industrial and commercial applications.

2. How does an induction motor work?

An induction motor works by using a rotating magnetic field to induce current in the rotor, which in turn creates a torque and causes the motor to spin. The speed of the motor is determined by the frequency of the AC power supply and the number of poles in the motor.

3. What is sequence reactance in an induction motor?

Sequence reactance refers to the impedance of the motor's stator and rotor windings. It includes the leakage reactance, which is the resistance of the windings to the flow of current, and the magnetizing reactance, which is the resistance to the creation of the magnetic field that drives the motor.

4. How does sequence reactance affect the performance of an induction motor?

The sequence reactance of an induction motor affects its starting torque, speed, and efficiency. A higher sequence reactance can result in a lower starting torque and a higher slip, which means the motor will take longer to reach its full speed and may be less efficient. It also determines the maximum amount of current that can flow through the motor.

5. How can the sequence reactance of an induction motor be controlled?

The sequence reactance of an induction motor can be controlled by adjusting the design of the motor's stator and rotor windings. This can be done by changing the number of turns in the windings or the material used for the windings. It can also be controlled by using external devices such as variable frequency drives or soft starters.

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